Training on measurements to determine the characteristics of three-phase electrical systems is very useful for a deep knowledge of the theoretical aspects, particularly for electrical engineering undergraduates. The technological development requires the realization of tools which gradually familiarize the students with advanced technologies for measurement during the training activity. Three different tools have been implemented during the last three years in order to improve on purpose the didactic value of the laboratory sessions. In the first tool a complex hardware and software system...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
Maria Gabriella Masi, Lorenzo Peretto, Roberto Tinarelli, Luigi Rovati
The validation of any new model of the human response to flicker requires proper experimental data. Recently, studies have been carried out with the intent of achieving information relevant to the state of annoyance of a human being subjected to light flicker by analyzing the modification of the pupil size. Indeed, it is well known that pupil diameter changes according to the luminous flux variation. According to such a theory the authors developed a measurement system capable of tracing the pupil size variations in time under flicker conditions. This will result of help for further...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
ADC testing frequently confronts the problem of spectral purity of harmonic test signal. The majority of dynamic ADC test methods require test signal distortion at least 10 dB less than that of the tested ADC – the condition that cannot be practically fulfilled for testing up-to-date ADCs. More sophisticated approach to ADC testing applies the correction for test signal imperfections. In both cases test signal distortion has to be known – roughly in the first case and quite accurately in the second case. In this paper an easy method for the testing of signal spectral purity is proposed. Test...
The bandpass sigma delta analog-digital converters (BP ΣΔ ADC) represent the unconventional ADCs, which are mostly embedded into digital communication systems or direct conversion of the voltage vector into the digital complex number. The structure of the noise shaping feedback impacts dominantly S/N ratio. The various feedback structures of the BP ΣΔ ADC designed from their low-pass prototype will be presented in the paper. The impact of the proposed structures on the basic metrological parameters of the BPΣΔ ADC will be analyzed here.
The paper describes the design phase of a portable gonio-reflectometer for the measurements of the reflection properties of road paving directly on site. The importance of these measurements is highlighted, then the measuring procedure is briefly described together a presentation of the organization of the instruments itself and the design criteria. Attention is focused on the positioning of the light sources exciting the surface under analysis and on the errors which can appear in the evaluation of the performance of a road lighting plant designed on the measurements realized by the...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
The method of characterizing a tunable bench of filter in the visible range and the spectral responsivity of a CCD camera is described. The two instruments are joined to form an image spectroradiometer, the performances of which are estimated taking into account its ability in reconstructing the spectral radiance of the light. The criteria useful to compensate the effect of finite bandwidth of the tunable filter are presented showing the effectiveness of the correction in determining both the spectra and the colorimetric CIE Lxy coordinates of the analyzed coloured samples. The system...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
E. Hristoforou, E. Kayafas, A. Ktena, DM Kepaptsoglou
In this paper we illustrate that magnetic hysteresis affects the uncertainty of sensors based on magnetic phenomena and materials. Testing various magnetic techniques, we conclude that sensor uncertainty can be optimized by both, the optimization of magnetic hysteresis and the operation in the magnetically reversible area of the material. Preliminary modelling results are in agreement with our experimental findings.
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
The development of system for linking the kilogram to electrical quantities is described in this paper. The method is based on a multifilar pendulum interacting with a coil, where a variable electromotive force that produces a current in the coil and in a suitable external resistor is generated. The electrical energy dissipated is measured and the mass is evaluated from this energy and from the kinematics of the pendulum.
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download
Linus Michaeli, Ján Šaliga, Michal Sakmár, Ján Buša
The paper presents a new approach to processing of the cumulative code histograms obtained at ADC histogram testing by exponential stimulus signal. The analytical base model requires calculation of logarithms that may not be convenient for implementation in some applications. The authors proposed two new approximation models of cumulative and code histograms derived from the analytical base model: recurrent model with rectangular rule and asymptotic model with the goal to simplify approximation process. The recurrent model is convenient for the implementation especially in digital signal...
The paper presents Visual Analyser, a free software tool developed by the research unit and suggested for use as a sophisticated virtual measurements educational laboratory for students. It can use either the sound card provided with all PC’s or dedicated hardware as the interface with the external world, and exploits the power of modern PC’s to achieve great performance. Visual Analyser includes a large set of instruments including a spectrum analyzer, a waveform generator, an oscilloscope and many other signal processing tools. For its special features Visual Analyser has been adopted by...
Exploring New Frontiers of Instrumentation and Methods for Electrical and Electronic Measurements · TC4 · 2008 · Download